This invention relates to liquid concentrates of water-insoluble agricultural chemicals (hereinafter referred to agrochemicals) and to a process for producing these concentrates.
Agrochemicals such as, for example, biocides, herbicides, insecticides and even fertilizers contain organic compounds which are insoluble or poorly soluble in water. In order to convert these agrochemicals into a form in which they are easy to handle by the user, they are often marketed as concentrated solutions in suitable organic solvents, for example alkyl benzene. Before use, these solutions have to be further diluted to the required concentrations. However, the use of these organic solvents is undesirable for economic reasons and above all for ecological reasons. Accordingly, there is a need for water-based concentrates of the agrochemicals in question.
WO 95/28083 describes water-based surfactant mixtures containing an alkyl naphthalene sulfonate and alkyl (oligo)glycosides and at least one pesticide and optionally other agrochemicals. EP 511 611 B1 describes aqueous solutions of the herbicide glufosinate ammonium. It is also mentioned in the specification that the claimed solutions may also contain other water-insoluble constituents in emulsified form. However, only aqueous solutions of the herbicide are disclosed in the Examples.
The known water-based formulations often show performance-related disadvantages in practice. Thus, the emulsions can separate on dilution with water. This problem occurs in particular where electrolyte-containing water, for example tap water, is used for dilution because the salt ions can upset the hydrophilic/lipophilic balance of the emulsifiers at the water/oil interface. In addition, problems arise during storage at low temperatures, for example below 10.degree. C., because in that case the emulsion often has to be rehomogenized before use.
Accordingly, the problem addressed by the present invention was to provide ecologically safe, low-temperature-stable aqueous emulsions of water-insoluble or substantially water-insoluble agrochemicals with virtually unlimited dilutability.